Method of annealing reflective photomask by using laser

Abstract

A laser annealing method performed on a reflective photomask may include preparing a reflective photomask including a pattern area and a border area surrounding the pattern area and irradiating a laser beam onto the border area of the reflective photomask. The irradiating of the laser beam may include split-irradiating a plurality of laser beam spots onto the border area. Each of the plurality of laser beam spots may be shaped using a beam shaper. The beam shaper may include a blind area, a transparent area at a center of the blind area, and a semitransparent area between the blind area and the transparent area. Each of the plurality of laser beam spots may include a center portion passing through the transparent area and having a uniform energy profile and an edge portion passing through the semitransparent area and having an inclined energy profile.

What is claimed is: 
     
         1 . A laser annealing apparatus comprising:
 a laser source;   a collimator;   a beam shaper;   a projection lens; and   a mask stage,   wherein the beam shaper comprises a blind area, a transparent area at a center of the blind area, and a semitransparent area between the blind area and the transparent area.   
     
     
         2 . The laser annealing apparatus of  claim 1 , wherein the transparent area has a rectangular shape, and the semitransparent area has a frame shape surrounding the transparent area. 
     
     
         3 . The laser annealing apparatus of  claim 1 , wherein the semitransparent area comprises bars or segments at opposite sides of the transparent area. 
     
     
         4 . The laser annealing apparatus of  claim 1 , wherein the semitransparent area of the beam shaper has a transparency gradient which increases from the blind area toward the transparent area. 
     
     
         5 . The laser annealing apparatus of  claim 4 , wherein the semitransparent area comprises a plurality of cut-out portions each having at least one of a stepped shape, a slit shape, a funnel shape, and a hole shape. 
     
     
         6 . The laser annealing apparatus of  claim 4 , wherein the semitransparent area has a transparency variation at least three times over the semitransparent area. 
     
     
         7 . The laser annealing apparatus of  claim 1 , wherein the beam shaper comprises a light blocking layer defining the blind area and a semitransparent layer defining the semitransparent area. 
     
     
         8 . The laser annealing apparatus of  claim 7 , wherein the beam shaper further comprises a transparent substrate, and the light blocking layer and the semitransparent layer are on the transparent substrate. 
     
     
         9 . The laser annealing apparatus of  claim 1 , wherein
 the transparent area is an empty space, and   the semitransparent area comprises a plurality of cut-out portions.   
     
     
         10 . A laser annealing apparatus comprising:
 a laser source;   a collimator;   a beam shaper;   a projection lens; and   a mask stage,   wherein the laser source generates a laser beam having a pulse shape.   
     
     
         11 . The laser annealing apparatus of  claim 10 , wherein the laser beam is irradiated to the beam shaper through the collimator, and
 the beam shaper shapes the laser source into a plurality of laser beam spots.   
     
     
         12 . The laser annealing apparatus of  claim 11 , wherein an energy profile of the laser beam has a gaussian shape, and an energy profile of each of the plurality of laser beam spots has a top hat shape. 
     
     
         13 . The laser annealing apparatus of  claim 11 , wherein the projection lens irradiates the plurality of laser beam spots onto a border area of a reflective photomask. 
     
     
         14 . The laser annealing apparatus of  claim 11 , wherein an energy profile of the center portion of each of the plurality of laser beam spots is flat and has a width of about 100 μm to about 200 μm, and
 an energy profile of an edge portion of each of the plurality of laser beam spots is inclined and has a width of about 5 μm to about 50 μm. 
 
     
     
         15 . The laser annealing apparatus of  claim 11 , wherein a split pitch of the plurality of laser beam spots is less than a width of each of the plurality of laser beam spots. 
     
     
         16 . The laser annealing apparatus of  claim 15 , wherein the split pitch of the plurality of laser beam spots is 0.5 to 0.9 times the width of each of the plurality of laser beam spots. 
     
     
         17 . The laser annealing apparatus of  claim 11 , wherein the plurality of laser beam spots have a pulse shape, and
 a duration of a pulse of each of the plurality of laser beam spots is about 10 μs or less.   
     
     
         18 . The laser annealing apparatus of  claim 11 , wherein a spot shape of each of plurality of the laser beam spots is rectangular. 
     
     
         19 . The laser annealing apparatus of  claim 11 , each of the plurality of laser beam spots comprises a center portion where transmittance is not adjusted and an edge portion where transmittance is adjusted. 
     
     
         20 . The laser annealing apparatus of  claim 10 , wherein the beam shaper shapes an energy profile of an edge portion of the laser beam to be inclined.